Dynamics in the presence of attractive patchy interactions

Area of Science:

• Soft Matter Physics
• Computational Chemistry
• Statistical Mechanics

Background:

• Understanding supercooled liquids and their dynamic arrest is crucial for materials science.
• Previous models often exhibit gas-liquid spinodals, limiting supercooling.
• Sticky particle models offer insights into network formation and anomalous behavior.

Purpose of the Study:

• To investigate the thermodynamic and dynamic properties of a sticky hard-sphere model.
• To explore supercooling behavior and network formation in the absence of a gas-liquid spinodal.
• To develop and apply a novel event-driven molecular dynamics algorithm for hard bodies with attractive patches.

Main Methods:

• Extensive Monte Carlo simulations.
• Development and implementation of a new event-driven molecular dynamics algorithm.
• Analysis of thermodynamic properties (density anomalies) and dynamic properties (dynamics, isodiffusivity, dynamic arrest).

Main Results:

• Evidence of density anomalies in deep supercooled states.
• Supercooling without gas-liquid spinodal over a wide range of packing fractions.
• Formation of a stable, fully connected tetrahedral bond network around optimal packing.
• Anomalous dynamics: acceleration with both increasing and decreasing packing fraction near optimal conditions.
• Mapping of isodiffusivity lines and the dynamic arrest line in the phase diagram.

Conclusions:

• The sticky hard-sphere model exhibits unique thermodynamic and dynamic properties, including density anomalies and anomalous acceleration of dynamics.
• The model provides a framework for understanding gel formation and dynamically arrested states in colloidal systems and proteins.
• The developed simulation algorithm enables the study of complex interactions in soft matter systems.